Damper disc

ABSTRACT

A damper disc in which an input plate, an output plate, and damper discs for coupling them are disposed, and moreover damper spring holding plates, and driving plates disposed between adjacent springs are provided as mutually independent parts, the fixing part to be fixed to the input plate, and the outside support part and inside support part for supporting the outer circumference of the damper springs from outward and inward in the disc radial direction are provided on the holding plates, the fixing part fixed to the input plate and the coupling part to be coupled to the end of the spring are disposed on the driving plates, and a part to be fitted to the outer circumference of the outside support part of the holding plate is disposed on the outer circumference of the input plate.

This application is a continuation of application Ser. No. 465,207 filedMar. 6, 1990, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a damper disc used in a lock-up clutchof automotive torque converter or the like, and more particularly to theimprovement of the structure for holding the damper spring in suchdamper disc.

2. Description of the Prior Art

In the Japanese Utility Model Application 61-170593 by the presentapplicant, a damper disc similar to the present invention is disclosed.Such damper disc comprises an input plate (piston) mounting an abrasionfacing for input, an output plate fixed to turbine (turbine shell orturbine hub), and a damper spring (coil spring) for coupling the twoplates, and also a holding plate for supporting the spring is provided.

This holding plate is fixed to the input plate, and a linkage part(pawl) linking in the circumferential direction is provided at the endportion of the spring. Therefore, the input plate is coupled to thespring by way of the holding plate. The holding plate is also designedto hold the spring in the radial direction, and accordingly it comprisesa tubular inside support part stretching along the inner circumferenceof the spring, and a tubular outside support part stretching along theouter circumference of the spring. Furthermore, there is also an outsidepart on the outer circumference of the input plate.

According to this structure, when the spring is about to move in theoperating state outward in the radial direction by the centrifugalforce, the spring is supported by this outside support part to arrestsuch movement, so that the specified action may be effected securely bystabilizing the position of the spring. In this operation, moreover,since the outer circumference of the outside support part is supportedby the outer end of the input plate, extreme deformation of the outsidesupport part in the radial direction by the centrifugal force from thespring may be prevented.

However, since the support plate is treated for hardening, the stiffnessis high, and the input plate is also high in stiffness, and therefore itis difficult to assemble the holding plate into the input plate byelastically deforming the both plates in the assembling process. As aresult, considering the dimensional errors of the both plates, in theassembling process, it is necessary to set the outside diameter of thesupport part smaller than, if very slightly, than the outer end of theinput plate in order to fit the outside support part of the holdingplate into the outer end of the input plate. Accordingly, a slight gapis formed between the support part and the tubular part, and when thesupport part receives the centrifugal force from the spring as mentionedabove, the support part is deformed outward in the radial direction bythe portion of this gap, so that a crack may be formed in the holdingplate.

The invention is intended to present a structure capable of solving theabove problems.

SUMMARY OF THE INVENTION

To achieve the object, the invention presents a damper disc whereinplural holding plates for supporting the springs stretching in an arcform along each damper spring, and plural driving plates disposedbetween adjacent springs are provided as mutually independent parts,fixing parts to be fixed on input plates and outside support parts andinside support parts for supporting the outer circumference of thedamper springs from both inward and outward in the disc radial directionare disposed on the holding plates, fixing parts to be fixed on inputplates and linking parts to be linked to the end portions of springs inthe circumferential direction are disposed on the driving plates, theinput plates are coupled to the springs by way of the driving plates,and parts to be fitted with the outer circumference of the outsidesupport parts of the holding plates are disposed on the outercircumference of the input plates.

According to this structure, in the assembling work, when assembling theholding plate into the inside of the outer end of the input plate, sincethe holding plate is in an arc shape, the support part may be tightlyfitted to the inner circumference of the outer end of the input plate.

Therefore, in the running state, if a centrifugal force is applied tothe support part of the support plate from the spring, the support partwill be hardly deformed significantly outward in the radial direction.Besides, since the holding plate and driving plate are separate parts,if the support part of the holding plate is deformed somewhat togetherwith the outer end of the input plate, cracks will not be formed in theholding plate and driving plate, and in the boundary of the both plates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of a clutch disc according tothe invention,

FIG. 2 is a partially cut-away II--II view of FIG. 1.

FIG. 3 is an enlarged view of the portion marked by a circle at theupper end of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a longitudinal view of a clutch disc according to theinvention, and FIG. 2 is a partially cut-away II--II view of FIG. 1. Theillustrated clutch disc is incorporated into the torque converter, andforms a lock-up clutch. As shown in FIG. 1, the clutch disc comprises aninput plate 1, an output plate 2, a damper spring 3, a driving plate 4,and a holding plate 5.

The input plate 1 is an annular member extending approximately in theradial direction of an output shaft 6 (of which only center line isshown), and its inner part is slidably fitted on the outer circumferenceof a turbine hub 7. The outer circumference of the input plate 1indicated by reference number 10 is annular and is extending in theradial direction of the output shaft 6, and an annular facing 11 isadhered to one surface of this part 10.

In the clutch cut-off state in FIG. 1, the facing 11 is opposite with agap to the inside of a front cover 12. The front cover 12 is a memberfor composing the input part of the torque converter, and is coupledwith the engine flywheel (not shown), and the outer front end part (notshown) is fixed to the impeller of the torque converter.

Although not shown in the drawing, the control device of the lock-upclutch controls the oil pressure on both sides of the input plate 1, andwhen the input plate 1 is moved in the direction of arrow A by such oilpressure, the facing 11 abuts against the front cover 12, so that thetorque is transmitted from the front cover 12 to the input plate 1,thereby connecting the clutch.

The output plate 2 is positioned at the opposite side of the front cover12 across the input plate 1, and the inner circumferential part is fixedto the turbine hub 7. The outer circumference of the output plate 2 iscoupled with the input plate 1 by way of the damper spring 3 asdescribed later. Therefore, when the clutch is connected in this way,the torque transmitted from the front cover 12 to the input plate i istransmitted to the output plate 2 by way of the damper spring 3, and isfurther transmitted to the output shaft 6 from the output plate 2 by wayof the turbine hub 7.

As shown in FIG. 2, there are plural (eight, in this embodiment) dampersprings 3 disposed at intervals in the circumferential direction of theclutch disc, individually extending in the circumferential direction (inan arc form) near the outer circumference of the input plate 1.

The driving plate 4 is disposed between adjacent two damper springs 3each, and comprises a linkage part 15 in a folding structure, and a flatfixing part 16 integrally stretching inward in the radial direction fromthe inside of the linkage part 15. Each fixing part 16 is fixed to theinput plate 1 by means of two rivets 17. As shown in FIG. 1, the linkagepart 15 is approximately in an S-form in the section in its radialdirection. As shown in FIG. 2, the linkage part 15 is inserted betweenadjacent two damper springs 3 so as to be engaged with the end portionof the damper springs 2 in the disc circumferential direction.

On the outer circumference of the output plate 2, a linkage part 8 offolding structure is provided. This linkage part 18 is placed betweenthe intermediate part and outer part of the linkage part 15 ofS-section, and is engaged with the end portions of the damper springs 3at its both sides in the circumferential direction.

There are as many holding plates 5 as the damper springs 3, and they areindividually disposed along the damper springs 3. As shown in FIG. 1,each holding plate 5 integrally comprises an annular part 20, an outsidesupport part 21, an inside support part 22, and a fixed leg part 23.

The annular part 20 has its section extended in the radial direction ofthe output shaft 6, and is located between the part 10 and damper spring3 in the state of tightly contacting with the part 10 of the input plate1.

The outside support part 21 is projecting from the outer circumferenceof the annular part 20 approximately in the axial direction (thedirection parallel to the output shaft 6) up to the outside in theradial direction of the damper spring 3, and its front end part 25 isbent inward in the radial direction along the outer circumference of thedamper spring 3. Therefore, the outside support part 21 supports thedamper spring 3 at the outside of spring 3 in the radial direction ofinput plate 1.

The inside support part 22 projects from the inner circumference of theannular part 20 in the same direction as the outside support part 21,and its front end part is bent outward in the radial direction.Therefore, the inside support part 22 supports the damper spring 3 fromthe inside of spring 3 and in the radial direction of input plate 1.

As shown in FIG. 2, the circumferential length of the annular part 20and outside support part 21 is nearly same as that of the damper spring3. The circumferential length of the inside support part 22 is slightlyshorter than that, and it is disposed at other parts than the both endportions of the holding plate 5.

The fixed leg part 23 is extending from both end portions of the annularpart 20 inward in the radial direction, and is fixed to the input plate1 by the rivets 17 in the state of being placed between the fixing part6 of the adjacent driving plate 4 and the input plate 11.

On the outer edge of the input plate 1, there is a part 30 tightlyfitted to the outer circumference of the outside support part 21.Furthermore, at the front end portion of the part 30, plural foldingprotrusions 31 are disposed at intervals in the circumferentialdirection, and these protrusions 31 are tightly fitted to the outercircumference of the folding front end portion 25 of the holding plate5.

In this structure, the torque transmitted to the input plate 1 isfurther transmitted to the damper spring 3 from the linkage part 15 ofthe driving plate 4 as mentioned above, and is also sent into thelinkage part 18 of the output plate 2 from the damper spring 3. Thus,the damper spring 3 is compressed, but however the damper spring 3 isextended or contracted, the holding plate 5 securely supports the damperspring 3 in the axial direction and radial direction, thereby preventingthe damper spring 3 from being dislocated from the specified position.

In particular, when the clutch disc rotates at high speed, a strongcentrifugal force is generated in the damper spring 3, and itscentrifugal force is transmitted to the outside support part 21 of theholding plate 5, but since the outside support part 21 is in tightcontact with the part 30 as mentioned above, the outside support part 21will not be deformed significantly. Besides, since the holding plate 5and driving plate 4 are different parts, if the holding plate 5 isdeformed somewhat together with the part 30, crack will not be formed inthe holding plate 5 or driving plate 4 or in the boundary of the bothplates 4, 5.

Referring now to the assembling work, since the holding plate 5 is anarc-shaped part, the outside support part 21 can be assembled into theinput plate 1 by tightly contacting with the inner circumference of thepart 30. Therefore, as mentioned above, the deformation of the outsidesupport part 21 may be suppressed by the part 30.

The function of the parts is as mentioned above, and in considerationthereof, the dimensions and material characteristics of the drivingplate 4 and holding plate 5 are selected as follows.

That is, each holding plate 5 is made of a tough thin plate large in theallowable elastic deformation on the whole. Each driving plate 4 is madeof a rigid, relatively thick plate treated for hardening. Of course, theinput plate 1 is made of a thick (strong and rigid) plate.

Thus, according to the invention, since the holding means for holdingthe damper spring 3 and the coupling means for coupling with the damperspring 3 are composed of separate members (holding plate 5 and drivingplate 4), they may be formed by using the plate materials having thethickness and quality suited to different applications (holding ofspring, and coupling). Therefore, preventing breakage of the holdingplate 5, the rotation strength of the entire clutch disc may beenhanced.

Besides, since a thin member may be used for the holding plate 5, thematerial cost and weight may be reduced. Of course, since the holdingplate 5 may be assembled by tightly contacting with the part 30 of theinput plate 1, the damper spring 3 may be supported in stable state alsoin this respect. Moreover, by using a thin member for the holding plate5, the damper spring 3 of a large diameter may be used within a limitedspace, and therefore the vibration absorption may be enhanced.

Still more, since the driving plate 4 and holding plate 5 are composedof plural parts, the material yield is improved as compared with thecase of forming the entire structure by using one annular part, and whatis more the complicated window opening and other machining are notneeded, and the process may be simplified.

In addition, according to the invention, since the individual holdingplates 5 are made of members stretching in the circumferential directionin a relatively short range, the allowable deflection of the outsidesupport part 2 is large. Therefore, for example, when assembled with adimensional error, if a gap is produced between the outside support part21 of the holding plate and the outside part 30 of the input plate 1 todeflect the outside support part 21 outward in the radial direction bycentrifugal force in operating state, formation of crack due todeflection in the holding plate 5 may be effectively prevented. Ifcracked, propagation of crack may be arrested within the individualholding plates 5.

What is claimed is:
 1. A damper disc comprising an annular input plate,an annular output plate, and plural damper springs for coupling saidinput and output plates in the circumferential direction of rotation ofsaid plates, said damper springs being disposed at intervals in thecircumferential direction of said input and output plates and extendingin an arc along the circumferential direction of said input and outputplates, damper spring holding plates interposed within a circular recessformed at the circumferential edge portion of said input plate and fixedto the input plate and extending in an arc in the circumferentialdirection of the input plates for supporting said damper springs fromthe inside and outside of said damper springs in the radial direction ofsaid input plate and driving plates fixed to said input plate anddisposed between ends of adjacent damper springs, said holding plateseach having a pair of fixed leg parts extending radially inwardly at theopposite end portions of said holding plates and secured to said inputplate, said driving plates each having a fixed part secured with saidfixed leg parts of said adjacent holding plates to said input plate anda linkage part for linking the end portions of said adjacent dampersprings to be compressible in the circumferential direction of saidinput and output plates.